As is well known in the literature, continuous-flow or "curtain" electrophoresis is an electrokinetic separation technique which utilizes both an electric field and a fluid flow perpendicular to that field to cause a continuous flow of electrolytes to separate on the basis of their charge-to-mass ratios (see, e.g., Deyl, Z., Electrophoresis: A Survey of Techniques and Applications, p. 261, Elsevier Scientific Publishing Co., New York, 1979). There are a number of problems associated with this technique, but perhaps the most serious shortcoming is the fact that the species which travel the farthest tend to become more diffuse as they move along the path of the electric field. The end result is that those species which should have the greatest resolution, i.e., those with the greatest electrophoretic mobility, actually lose resolution due to the effects of diffusion.
The aforesaid copending U.S. patent application Ser. No. 791,605 now U.S. Pat. 4,670,119 resides in an apparatus and process for isoelectric focusing which comprises: confining an electrolyte solution in a focusing chamber having an anode end and a cathode end; establishing an electric current through said solution; and providing a plurality of electrode pairs bordering said focusing chamber and applying a non-linear voltage gradient to the electrode pairs along the length of the focusing chamber, whereby the ionic species present in said electrolyte will be concentrated at either the anode or cathode end thereby establishing a steady-state pH gradient in said focusing chamber. It would be highly desirable to utilize features of the aforesaid copending application Ser. No. 791,605 in order to improve sample resolution in an electrophoresis chamber wherein the samples have divergent electrophoretic mobility, and even widely divergent electrophoretic mobility.
It is, therefore, an object of the present invention to provide a novel electrophoretic separation technique which will sort a mixture of macromolecules, such as serum proteins, DNA fragments, enzymes or the like, on the basis of their electrophoretic mobilities.
It is a further object of the present invention to allows such separation to be made in a continuous flow-through fashion.
It is another object of the present invention to provide a means by which the electric field may be configured to counteract the forces of diffusion during the separation run, such that species being resolved do not show the normal tendency to lose resolution as they travel farther along the path of the electric field.
It is a further object of the present invention to provide an apparatus and process which achieves the objectives as aforesaid utilizing features described in said copending U.S. patent application Ser. No. 791,605 now U.S. Pat. No. 4,670,119 and allowing maximum flexibility in the selection of the voltage gradient through the array of electrode pairs described therein.
It is a still further object of the present invention to provide an apparatus and process as aforesaid which is simple and convenient to use.
Further objects and advantages of the present invention will appear hereinbelow.